1. Field of the Invention
The present invention relates generally to computer systems, and more particularly to apparatus for coupling expansion cards within a computer system.
2. Description of the Related Art
Computer systems in general and International Business Machines (IBM) compatible personal computer systems in particular have attained widespread use for providing computer power to many segments of modern society. A personal computer system can usually be defined to include a system unit having a system processor and associated volatile and non-volatile memory which are contained within a desk top, floor standing, or portable housing. A personal computer system can also include a display monitor, a keyboard, one or more diskette drives, a fixed disk storage device and an optional printer. One of the distinguishing characteristics of these systems is the use of a system board to electrically connect these components together. These personal computer systems are information handling systems which are designed primarily to give independent computing power to a single user (or a relatively small group of users in the case of personal computers that serve as computer server systems) and are inexpensively priced for purchase by individuals or small businesses.
A personal computer system may also include one or a plurality of input/output (I/O) devices (i.e., peripheral devices) which are coupled to the system processor and which perform specialized functions. Examples of I/O devices include modems, sound and video devices or specialized communication devices. Mass storage devices such as hard disks, CD-ROM drives and magneto-optical drives are also considered to be peripheral I/O devices. It is known to provide certain I/O devices as expansion cards. Computer systems are customarily provided with metal card cage structures within the housings of the computer systems. The card cage structures are adapted to receive and removably support a plurality of expansion cards.
When operatively installed in the computer system, an expansion card upgrades or expands the operating capabilities of the computer. Expansion cards may be installed in the computer during its original manufacture or may be subsequently installed by the user. Typical types of expansion cards include network, sound, graphics accelerator and multimedia cards.
An expansion card is a relatively small, generally rectangularly shaped printed circuit board having a connector edge portion along one side edge. The connector edge portion operatively couples with a corresponding socket portion of the system board via a card slot to operatively couple the installed card to the motherboard. The card slots of the cage structure are relatively oriented in a manner such that the expansion cards installed therein are arranged in a spaced apart, parallel, facing series with end edges of the cards being aligned with one another.
Extending along these aligned end edge portions of the expansion cards are sheet metal connecting brackets having outwardly bent securement tab portions positioned adjacent the side edge portions of the cards opposite their connector edge portions. These tab portions rest upon an in-turned side wall ledge of the cage structure and have notches formed therein that overlie and register with a spaced series of threaded circular openings in the ledge. Each bracket tab is removably secured to the ledge by a screw that extends through the tab notch and is threaded into its associated ledge opening. This individual securement of the bracket tabs to the cage structure ledge serves to anchor one end of the installed expansion cards in place within the cage structure.
The expansion cards added into a personal computer by a manufacturer or an individual are often subjected to substantial shock and vibration during computer assembly and when the computer is transported. This shock and vibration can result in the expansion cards becoming dislodged from their interface connector on the systems motherboard. This is especially true because, as mentioned above, the card is typically held in place by a single screw at one end of the expansion card. The other end of the card is often unrestrained in the axis perpendicular to the motherboard and in all other axes.
From the foregoing it can be readily seen that it is desirable to provide an improved apparatus for removably retaining expansion cards in an associated support cage structure in order to eliminate or at least substantially minimize the above mentioned problems associated with the sole conventional use of individual card bracket tab retaining screws. It is accordingly an object of the present invention to provide such an improved apparatus.